Sphere No.44 (Mar 2018)

to water in liquid or granular form, or through salt chlorination, it’s this same hypochlorous acid that kills the things we don’t want in the water. Salt-chlorination systems smooth out the introduction of this hypochlorous acid into the pool water – and this makes all the difference to swimmers. Cheetham Salt provides staff training for pool equipment shops and hosts How to use Pool Salt videos on its customer websites to ensure owners get proper instruction on how to use their salt-chlorination system. But with such widespread adoption, Australians can simply knock on their friendly neighbour’s door for a little help when they get started. People around the world with year-round pools and seasonal pools alike, may start looking Down Under for a new way to enjoy their private pools, with open eyes underwater and happy hair, and find a better way to enjoy their aquatic life. They may find that Australian saltwater- chlorinated pools don’t have sharks and crocodiles, but rather a high-technology solution that will sweeten the taste of their summertime swimming experience. Sphere #44 2018 21 << It’s there – you just can’t taste it. Swimmers also say they avoid the irritation associated with traditional liquid chlorination. The word most commonly used is the ‘softer’ feel of the water – an absence of harsh chemical contents affecting their hair and skin. This technology is popular with Australians, with almost 75 per cent of Australian households with private backyard pools having installed salt-chlorination systems, with market share growing at a rate of about 10 per cent a year. Regarding cost, the normal payback period for the cost of installing and maintaining a saltwater-chlorination system is about 10 years. The initial salt-chlorination hardware can cost up to AUD1,000, and chlorinator cells need to be replaced around every five years, costing AUD400 each. However, over a 10-year period, the total cost of a saltwater system compared to using liquid or granular chlorine is approximately the same, due to the higher cost of liquid chlorine and the higher volume of chlorine required to maintain pool cleanliness. This doesn’t include the value inherent in a more pleasant bathing experience for pool-mad Aussies who spend countless hours in their backyard pools. Regular swimmers change their conversation from hair remediation to more weighty subjects, such as how to best cook their snags (sausages) and prawns on the barbie. Salty secrets All this begs the question: How does it work? Doesn’t the ‘Cl’ in NaCl mean chlorine? And why call it ‘salt chlorination’ if no liquid chlorine is used? The secret lies in the fact that chlorine, used to kill bacteria and viruses, is still the means of disinfection. It’s how it is delivered into the water, and in what concentrations, that makes all the difference. Salt-chlorination systems use a salt- chlorine generator to free the chlorine ions from NaCl at an effective, moderated and even concentration over a longer period of time. This contrasts sharply with manually adding high doses of liquid or granular chlorine to pool water. Rather than dumping a high concentration of chlorine into the pool, the salt-chlorination system continually adds a moderate amount of chlorine over time. A 25kg bag or two of Cheetham Pool Salt, which is simply NaCl, is poured into the pool water and quickly dissolves. As discussed, as the concentration in parts per million is very low, swimmers do not even taste or notice the salt. The pool water is then slowly pumped through to the heart of the salt-chlorination system – the chlorine generator. This is a simple set of electrolysis metal plates that carry a low-voltage current. When salt-infused water passes over the plates, electrolysis occurs and this splits the salt (NaCl) and combines it with water (H 2 O) to produce small amounts of hypochlorous acid (HClO). Whenever chlorine is added The lack of taste is a distinguishing feature of saltwater-chlorinated pools.